Learn how salts are formed through word and symbolic equations, and explore step-by-step methods for preparing salts like magnesium sulphate in the lab. Ideal for students and educators alike.
📘 Introduction
Salt formation is a fundamental concept in chemistry, connecting the topics of neutralization reactions, acid-base interactions, and ionic bonding. Whether in a lab experiment or in real-life applications, the formation of salts involves predictable reactions between acids and bases, and can be represented using word and symbolic (chemical) equations.
In this blog, you’ll learn:
- How salts are formed using word and symbolic equations.
- The process of preparing salts like magnesium sulphate in the laboratory.
- Practical examples and tips for mastering these concepts.
Let’s get started!
🔹 What Is a Salt?
In chemistry, a salt is formed when an acid reacts with a base (alkali) or metal during a neutralization reaction. The reaction produces:
- A salt
- And water (in case of alkalis or bases)
- Sometimes hydrogen gas (when acids react with metals)
🧾 1. Word and Symbolic Equations for Salt Formation
Understanding both word equations and chemical (symbolic) equations helps students and professionals visualize and explain reactions clearly.
✅ A. Acid + Base → Salt + Water
This is a typical neutralization reaction.
Word Equation:
Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water
Symbolic Equation:
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
✅ B. Acid + Metal → Salt + Hydrogen
This type of reaction produces a salt and hydrogen gas.
Word Equation:
Sulphuric acid + Magnesium → Magnesium sulphate + Hydrogen
Symbolic Equation:
H₂SO₄(aq) + Mg(s) → MgSO₄(aq) + H₂(g)
✅ C. Acid + Metal Carbonate → Salt + Water + Carbon dioxide
Word Equation:
Nitric acid + Calcium carbonate → Calcium nitrate + Water + Carbon dioxide
Symbolic Equation:
2HNO₃(aq) + CaCO₃(s) → Ca(NO₃)₂(aq) + H₂O(l) + CO₂(g)
✅ D. Acid + Metal Oxide → Salt + Water
Word Equation:
Hydrochloric acid + Copper(II) oxide → Copper(II) chloride + Water
Symbolic Equation:
2HCl(aq) + CuO(s) → CuCl₂(aq) + H₂O(l)
🧠 Quick Tip for Students:
- The metal part of the salt comes from the base, metal, or carbonate.
- The non-metal part of the salt comes from the acid (e.g., HCl gives chlorides, H₂SO₄ gives sulphates).
🧪 2. Preparation of Salts Like Magnesium Sulphate
🎯 Goal:
To prepare magnesium sulphate (MgSO₄) by reacting magnesium with sulphuric acid.
📌 Method 1: Using a Metal (Magnesium) and an Acid (Sulphuric Acid)
🧴 Materials Required:
- Magnesium ribbon
- Dilute sulphuric acid
- Beaker
- Filter funnel and paper
- Evaporating dish
- Bunsen burner or hot plate
🔬 Step-by-Step Procedure:
Step 1: Reaction Setup
- Pour about 25 mL of dilute sulphuric acid into a beaker.
- Add small pieces of magnesium ribbon to the acid slowly.
Step 2: Observe the Reaction
- You will notice fizzing or effervescence due to the release of hydrogen gas.
- Continue adding magnesium until the reaction stops (i.e., when no more gas is produced).
- This means all the acid has been neutralized.
Reaction:
H₂SO₄(aq) + Mg(s) → MgSO₄(aq) + H₂(g)
Step 3: Filter the Mixture
- Use filter paper to remove any unreacted magnesium.
- The filtrate (solution that passes through) contains magnesium sulphate.
Step 4: Evaporate the Solution
- Heat the filtrate gently in an evaporating dish to reduce the volume of water.
- Once it reaches half the volume, allow it to cool slowly at room temperature.
- Crystals of magnesium sulphate will form.
Step 5: Dry the Crystals
- Carefully remove the crystals and dry them on filter paper or in a desiccator.
🧪 Alternative Method: Using Magnesium Oxide
Word Equation:
Sulphuric acid + Magnesium oxide → Magnesium sulphate + Water
Symbolic Equation:
H₂SO₄(aq) + MgO(s) → MgSO₄(aq) + H₂O(l)
This method is also common in labs and avoids the release of hydrogen gas.
🧑🏫 Tips for Practical Salt Preparation
- Always use dilute acids to control the reaction rate and prevent splashing.
- Add excess base or metal to ensure all the acid reacts.
- Filter out any excess solid to obtain a pure salt solution.
- Evaporate gently—do not boil dry, as overheating can decompose some salts.
- Allow slow cooling to get larger, purer crystals.
💡 Why Prepare Salts in the Lab?
- To study chemical reactions like neutralization.
- To produce salts for use in experiments, fertilizers, and treatments.
- To observe crystal formation and practice filtration and evaporation techniques.
🌍 Real-Life Applications of Magnesium Sulphate
- Used as Epsom salt in bath soaks to relieve muscle pain.
- Acts as a laxative and electrolyte replacement.
- Employed in agriculture to treat magnesium-deficient soils.
🔄 Recap: Salt Formation Pathways
| Type of Reaction | Products |
| Acid + Base | Salt + Water |
| Acid + Metal | Salt + Hydrogen |
| Acid + Metal Carbonate | Salt + Water + Carbon Dioxide |
| Acid + Metal Oxide | Salt + Water |
Conclusion
Salt formation is a core concept in chemistry that connects neutralization, reactions of acids, and real-life applications. Whether using word equations to introduce students to basic concepts or symbolic equations to deepen understanding, knowing how salts like magnesium sulphate are prepared brings chemistry to life.
By mastering both theory and practice, learners can grasp how common laboratory processes relate to everyday applications—from medicine and agriculture to health and hygiene.
📌 Featured Snippet Tip:
Q: What is the word and symbolic equation for the preparation of magnesium sulphate?
A:
Word Equation: Sulphuric acid + Magnesium → Magnesium sulphate + Hydrogen
Symbolic Equation: H₂SO₄ + Mg → MgSO₄ + H₂
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